class Cart < ApplicationRecord
	has_many :line_items, dependent: :destroy

	def add_product(product_id)
	current_item = line_items.find_by(product_id: product_id)
	if current_item
	current_item.quantity += 1
	else
	current_item = line_items.build(product_id: product_id)
	end
	current_item
	end

	def total_price
	line_items.to_a.sum { |item| item.total_price }
	end
end
